A diagnostic test used in cardiology is aortography wherein contrast agent is injected into the aortic root and subsequently into the coronary arteries while an image is taken. In this procedure, a large bolus of contrast agent is injected into the aortic root complex which branches into the right coronary artery (RCA) and the left coronary artery (LCA). In certain angled views, the images of these vessels may overlay each other, however, causing difficulty in their detailed visualization.
Accordingly, selective coronary angiography is a standard practice in cardiology. In this method, specially designed catheters are used to seek out the RCA and LCA for the direct injection of contrast agent. Two separate catheters must be used, with the LCA generally being easier to cannulate. Either coronary artery may present difficulty in cannulation.